Black Matte would cost the least. If the existing paint is in very good condition all you would need to do is spray on some matte clear coat.
Modern vehicles use a water based automotive paint. If you know how to use a paint spray gin and have access to a place to paint your car you could get...
You are going to need a larger bike. You will need to go to each manufacturer's website and checkout the detailed specifications on the larger bikes to get their weight capacity.
The Porsche is 9 years older and will cost a lot more money to maintain.
The Porsche will have a lot more miles on it and more wear and tare. Parts will cost much more and most of the work will need to be done by a professional mechanic.
I would choose the Mustang.
It will be worth your while to get a maintenance manual for this bike. Clymer sells a manual for this bike for $22.72 + shipping. See the link below.
It will have troubleshooting and repair information for your problem.
This manual will have detailed step by step instructions to correctly do...
Check the idle air control valve.
It is located on the fuel injection throttle body. The valve could be sticking or may have failed.
Remove the valve and clean the valve and port with spray carburetor cleaner. Check the wiring to the valve. Replace the valve if this does not work. They are...
First of all, motorcycle parts are expensive. It is unrealistic to expect to find cheap parts for any motorcycle.
Try the link below. They have parts for most Japanese bikes, even the older ones.